"Speaking for those of the younger generation, I cannot imagine a greater gift than that."

Dr Mangcu said it had been a conscious decision not to include South African writers in the latest lecture series and book.

"I felt that we often get bogged down in our petty differences," he explained.

He added though that the project of defining the meaning of Mandela would continue, and that South Africans would be asked to participate in future.

Veteran photographers

The exhibition mounted by the Nelson Mandela Foundation in Johannesburg documents the 1952 defiance campaign, when the ANC led a campaign of resistance against racially discriminatory laws.

It features the work of veteran photographers Alf Khumalo and Jurgen Schadeberg.

Alf Khumalo recalled an incident when he was photographing Mr Mandela during a trip to the United States in the 1990s.

"He told some people, 'This is Alf Khumalo, my colleague, he was also in jail'.

"Then everybody wanted to pose with me," Mr Khumalo said. "Mandela didn't mention I'd been to jail several times but for very short stints."

Mr Schadeberg said that although in the 1950s Mr Mandela was one among many notable anti-apartheid leaders, it was his serenity that left an impression.

"At the time there were a lot of great people around - many of them would be come very agitated but he was always in control - even now, you can see that he is calm, a man of peace," Mr Schadeberg said.